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From:   Vaibhav Jain <vaibhav@linux.ibm.com>
To:     Yosry Ahmed <yosryahmed@google.com>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Michal Hocko <mhocko@kernel.org>,
        Shakeel Butt <shakeelb@google.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        David Rientjes <rientjes@google.com>
Cc:     Tejun Heo <tj@kernel.org>, Zefan Li <lizefan.x@bytedance.com>,
        Roman Gushchin <roman.gushchin@linux.dev>,
        cgroups@vger.kernel.org, linux-doc@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        Jonathan Corbet <corbet@lwn.net>, Yu Zhao <yuzhao@google.com>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Wei Xu <weixugc@google.com>, Greg Thelen <gthelen@google.com>,
        Yosry Ahmed <yosryahmed@google.com>
Subject: Re: [PATCH resend] memcg: introduce per-memcg reclaim interface
In-Reply-To: <20220331084151.2600229-1-yosryahmed@google.com>
References: <20220331084151.2600229-1-yosryahmed@google.com>
Date:   Fri, 01 Apr 2022 14:09:25 +0530
Message-ID: <874k3d6vuq.fsf@vajain21.in.ibm.com>
MIME-Version: 1.0
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Yosry Ahmed <yosryahmed@google.com> writes:
> From: Shakeel Butt <shakeelb@google.com>
>
> Introduce an memcg interface to trigger memory reclaim on a memory cgroup.
<snip>

> +
> +	while (nr_reclaimed < nr_to_reclaim) {
> +		unsigned long reclaimed;
> +
> +		if (signal_pending(current))
> +			break;
> +
> +		reclaimed = try_to_free_mem_cgroup_pages(memcg,
> +						nr_to_reclaim - nr_reclaimed,
> +						GFP_KERNEL, true);
> +
> +		if (!reclaimed && !nr_retries--)
> +			break;
> +
> +		nr_reclaimed += reclaimed;

I think there should be a cond_resched() in this loop before
try_to_free_mem_cgroup_pages() to have better chances of reclaim
succeding early.

<snip>

-- 
Cheers
~ Vaibhav